Flame-retardant composite materials

The properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement are described. The resin matrices included: VPSP/BMI, a blend of vinylpolystyryl pyridine and bismaleimide; BMI, a bismaleimide; and phenolic and PSP, a polystyryl pyridine. The graphite fiber used was AS-4 in the form of either tape or fabric. The properties of these composites were compared with epoxy composites. It was determined that VPSP/BMI with the graphite tape was the optimum design giving the lowest heat release rate

The 1-((diorganooxyphosphonyl)-methyl)-2,4- and -2,6-diamido benzenes

1-((Diorgano oxyphosphonyl) methyl)-2,4- and -2,6-dinitro and diamino benzenes are prepared by nitrating an (organophosphonyl) methyl benzene to produce the dinitro compounds which are then reduced to the diamino compounds. The organo grounds (alkyl, haloalkyl, aryl) on the phosphorus may be removed to give the free acids (HO)2P(double bond O)single bond. The diamino compounds may be polymerized with dianhydrides or diacyl halides to produce fire and flame resistant polymers which are useful in the manufacture of aircraft structures

Urinary stone disease: Great progress with promise for the future.

Urinary calculus disease has been a scourge on mankind since ancient times. Research in the field has been hampered by lack of funds and the lack of cachet with the public such as seen with cancer or heart disease. In recent years there have been marked changes led by urologists in the diagnosis, treatment and long-term management of calculi

Price Squeeze in Practice: Is it a Profitable Strategy?

Price squeeze has been an important issue in the telecommunications market as many incumbent operators have exercised this strategy in order to foreclose competitive entrants (see Polo (2008), Bravo and Siciliani (2007), Geradin and O'Donoghue (2005) and Crocioni and Veljanovski (2003). The experience in all European cases considered in these studies shows the difficulty and complexity faced by regulators in implementing the imputation analysis. In the US some Courts have followed a different approach and some authors do not consider margin squeeze as an abuse by a dominant operator (see also Crandall and Singer (2007), Carlton (2008) and Sidak (2008)). The role of the present paper is to examine critically the decision of the Greek regulator on a price squeeze allegedly applied by the Greek incumbent OTE through its subsidiary OTEnet on the market for broadband services. In doing so, a number of important questions arise: Why the regulator used the REO test instead of the EEO test that has been applied in almost all antitrust cases? What is a legitimate or sufficient margin under which a margin squeeze occurs? Can a price squeeze lead to falling market shares for the incumbent and rising market shares for the entrants? Should the NCA intervene just after one year from the opening of the market? In this paper we attempt to answer the above questions and relate our results to the existing literature. --

A 10-watt CW photodissociation laser with IODO perfluoro-tert-butane

NASA has been investigating the feasibility of direct solar-pumped laser systems for power beaming in space. Among the various gas, liquid, and solid laser systems being proposed as candidates for solar-pumped lasers, the iodine photodissociation gas laser has demonstrated its potential for space application. Of immediate attention is the determination of system requirements and the choice of lasants to improve the system efficiency. The development of an efficient iodine laser depends on the availability of a suitable iodide which has favorable laser kinetics, chemically reversibility, and solar energy utilization. Among the various alkyliodide lasants comparatively tested in a long-pulse system, perfluoro- tert-butyl iodide, T-C4F9I, was found to be the best. However, the operating conditions for the laser medium in a continuously pumped and continuous-flow iodine laser differ considerably from those in the pulsed regime. The results of the continuous wave (CW)) laser performance from t-C4F9I are reported. Perfluoro- n-propyl iodide, n-C3F7I is used for comparison because of its universal use in photodissociation iodine lasers

Ureteroscopic treatment of larger renal calculi (\u3e2 cm).

OBJECTIVES: To evaluate the current status of ureteroscopic lithotripsy (UL) for treating renal calculi of \u3e2 cm, as advances in flexible ureteroscope design, accessory instrumentation and lithotrites have revolutionised the treatment of urinary calculi. While previously reserved for ureteric and small renal calculi, UL has gained an increasing role in the selective management of larger renal stone burdens. METHODS: We searched the available databases, including PubMed, Google Scholar, and Scopus, for relevant reports in English, and the article bibliographies to identify additional relevant articles. Keywords included ureteroscopy, lithotripsy, renal calculi, and calculi \u3e2 cm. Retrieved articles were reviewed to consider the number of patients, mean stone size, success rates, indications and complications. RESULTS: In all, nine studies (417 patients) were eligible for inclusion. After one, two or three procedures the mean (range) success rates were 68.2 (23-84)%, 87.1 (79-91)% and 94.4 (90.1-96.7)%, respectively. Overall, the success rate was \u3e90% with a mean of 1.2-2.3 procedures per patient. The overall complication rate was 10.3%, including six (1.4%) intraoperative and 37 (8.9%) postoperative complications, most of which were minor. The most common indications for UL were a failed previous treatment (46%), comorbidities (18.2%), and technical and anatomical factors (12.3%). CONCLUSIONS: UL is safe and effective for treating large renal calculi. While several procedures might be required for total stone clearance, UL should be considered a standard approach in the urologist\u27s options treating renal calculi of \u3e2 cm